Study on wintry comfort temperature and thermal improvement of houses in cold, temperate, and subtropical regions of Nepal

Abstract Nepalese households have been using electricity from hydropower plants at almost the lowest rate among other countries. Residents adjust their indoor environments by relying on very primitive methods. This study focuses on the thermal comfort of residents in Nepalese households and how it can be improved by enhancing the thermal insulation of the houses investigated. A field survey was conducted in winter in cold, temperate, and subtropical regions, and 839 thermal sensation votes were collected from all regions together with the measured indoor and outdoor temperatures. The mean comfort temperatures estimated using Griffiths’ method were 17.2 °C, 20.9 °C, and 21.7 °C in the cold, temperate, and subtropical regions, respectively. The indoor globe temperature of the cold region was significantly lower than the comfort temperature. The comfort temperature exhibited a large regional difference. The average measured indoor air temperatures in the cold, temperate, and subtropical regions were 10.9 °C, 18 °C, and 20 °C, respectively, and they were 6.3 °C, 2.9 °C, and 2 °C lower than the average estimated comfort temperature. In the cold region during winter, the indoor climate can be improved because the indoor temperature is rated as slightly uncomfortable. By enhancing the thermal insulation and reducing the infiltration, the indoor air temperature was found to increase by 1.1–1.8 °C. The findings of this study should be useful in providing a good indoor thermal environment for houses and energy-saving building design in Nepalese society.